(Note: This appendix is very much under development. Check back
periodically.)

It may seem silly to devote space to numbers as physicists by hypothesis
love numbers, but the standard undergraduate training of
physicists does not include a course in number theory per se, so most of
what they are likely to know is gleaned from at most one course in
complex numbers (math double majors and math minors excepted). This
chapter makes no attempt to present an exhaustive review of number
theory (however cool and worthy of a deeper treatment it might be) but
instead confines itself to just a few points of direct relevance to
electrodynamics.